220109991 has 16 divisors (see below), whose sum is σ = 301656960. Its totient is φ = 142682400.

The previous prime is 220109987. The next prime is 220109993. The reversal of 220109991 is 199901022.

It is not a de Polignac number, because 220109991 - 2² = 220109987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220109993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25816 + ... + 33266.

It is an arithmetic number, because the mean of its divisors is an integer number (18853560).

Almost surely, 2^220109991 is an apocalyptic number.

220109991 is a deficient number, since it is larger than the sum of its proper divisors (81546969).

220109991 is a wasteful number, since it uses less digits than its factorization.

220109991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7726.

The product of its (nonzero) digits is 2916, while the sum is 33.

The square root of 220109991 is about 14836.1043067242. The cubic root of 220109991 is about 603.7816621985.

The spelling of 220109991 in words is "two hundred twenty million, one hundred nine thousand, nine hundred ninety-one".